1. Field of the Invention
This invention relates to a lens barrier mechanism for an optical apparatus such as a camera, a lens barrel or the like.
2. Description of the Related Art
Many of the cameras manufactured these days to use noninterchangeable lenses (compact cameras) are of the so-called retractable mount type arranged to have the lens barrel stowed within the camera body when the lens barrel is not used for shooting. Each of the retractable mount type cameras is provided with a lens-barrel-interlocking type barrier mechanism which opens and closes in association with the drawing-out and drawing-in actions of the lens barrel. The lens barrier mechanisms provided in the retractable mount type camera are of many different kinds. Each of the known lens barrier mechanisms has been arranged such that its aperture is small relative to the diameter of the lens barrel when the barrier mechanism is fully open. Therefore, a space required for barrier blades of the barrier mechanism to retreat from an optical path in fully opening the barrier mechanism can be secured within the lens barrel without difficulty. Besides, it has been also possible to arrange the lens barrier mechanism to have a relatively simple structural arrangement.
Meanwhile, it has recently become popular to provide a camera with a panorama shooting mechanism which is arranged to show a shooting image plane in such a form that appears to be horizontally longer than a standard image plane and is called a panorama image plane. According to the known panorama shooting mechanism, however, the panorama image plane is obtained by merely reducing the vertical dimension of the standard image plane. It is thus hardly possible to attain a true panorama shot effect with the known panorama shooting mechanism. In view of this problem, there has been proposed a camera which is capable of giving a true panorama shooting effect by making the horizontal dimension of the shooting image plane truly larger than the standard image plane.
However, according to the proposed camera as mentioned above, it becomes difficult to secure a retreat space which is required for the barrier blades to retreat sideward from the front side of the lens when the barrier mechanism is fully opened, because the aperture of the barrier mechanism of such a camera is arranged to be horizontally larger than that of the conventional camera when the barrier mechanism is fully open. Therefore, the lens barrier mechanism of the camera of the proposed kind cannot be configured in a manner similar to the conventional lens barrier mechanism. The camera proposed thus has presented a problem.